Confirmation that pulse and continuous peracetic acid administration does not disrupt the acute stress response in rainbow trout

Abstract

A B S T R A C TPeracetic acid (PAA) is considered an eco-friendly alternative to other antimicrobial agents of common use in aquaculture. The literature suggests that fish can habituate to PAA exposure based on a reduction of the fish corticosteroid response to PAA administration after repeated exposures. If that is true, PAA would also be a good option from the point of view of fish physiology. However, stronger evidence is needed to confirm that the use of PAA is welfare-friendly to fish. Besides habituation, other hypothetical factors such as desensitization, physiological exhaustion or PAA-mediated endocrine disruption could potentially explain the reduction in the corticosteroid response after repeated/prolonged PAA exposure. In this study, rainbow trout that had been exposed to PAA for several weeks were challenged with a secondary chasing stressor: fish were pursued with a dipnet for 1 min and their acute response was evaluated by measuring plasma cortisol, plasma glucose, plasma lactate and brain serotonergic activity. All fish were equally able to mount a normal physiological stress response to the secondary stressor independent of previous exposure to PAA. This suggests that the decrease in the cortisol response after repeated exposure to PAA, as seen in previous studies, is a true habituation to PAA administration, which supports the use of PAA as a welfare-friendly antimicrobial agent in aquaculture.

Crowding reshapes the mucosal but not the systemic response repertoires of Atlantic salmon to peracetic acid

“…Evidence of global molecular responses is lacking in our current understanding of the physiological consequences of PAA exposure in fish (Gesto, Liu, Pedersen, Meinelt, Straus, Jokumsen, 2018;Hushangi, Hosseini Shekarabi, 2018;Liu, Lazado, Pedersen, Straus, Meinelt, 2020). Here, we show that the transcriptome of the two mucosal tissues that directly interacted with PAA during treatment responded differently to PAA, with the gills exhibiting a stronger response than the skin (Figure 4).…”

“…It has been shown earlier in rainbow trout that the adaptive response to a secondary stress (i.e., chasing) was not altered by prior PAA exposure (Gesto, Liu, Pedersen, Meinelt, Straus, Jokumsen, 2018). However, no data are available to indicate how stress (e.g., crowding) before treatment influences responses to subsequent PAA exposure.…”

“…The chemical behaviour of PAA in both freshwater and seawater matrices is well-described Pedersen, Meinelt, Straus, 2013) and the toxicity of PAA towards several aquaculture fish has been reported . Most of the studies documenting its physiological impacts on fish have focused on rainbow trout (Oncorhynchus mykiss), where PAA exposure has been demonstrated to trigger oxidative stress, though the trout were able to respond to the oxidant by activating physiological adaptive mechanisms including immunity and the neuroendocrine axis (Gesto, Liu, Pedersen, Meinelt, Straus, Jokumsen, 2018;Liu, Lazado, Pedersen, Straus, Meinelt, 2020). Using a limited panel of known markers for stress, we have earlier reported that salmon post-smolts were able to mount systemic and mucosal responses to PAA concentrations ranging from 0.6 to 4.8 ppm (Soleng, Johansen, Johnsen, Johansson, Breiland, Rørmark, Pittman, Pedersen, Lazado, 2019).…”

Effect of disinfection with peracetic acid on the microbial community of a seawater aquaculture recirculation system for Pacific white shrimp (Litopenaeus vannamei)

“…For example, it could be shown that adding 10 mg PAA/L can effectively suppress the pathogenicity of the oomycete, Aphanomyces astaci , the pathogenic agent in crayfish plague (Jussila, Makkonen, & Kokko, 2011). For fish, PAA seems to be welfare‐friendly, as a true habituation of fish to the substance associated with a decrease in the cortisol response after repeated exposure to PAA has been seen (Gesto et al., 2018; Liu, Pedersen, et al, 2017). The toxicity of PAA varied between different fish species, and the mean 24‐hr LC 50 values ranged from 2.8 to 9.3 mg/L PAA (Straus, Meinelt, Liu, & Pedersen, 2018).…”

Control of off-flavor compounds in a full-scale recirculating aquaculture system rearing rainbow trout Oncorhynchus mykiss

“…In this study, neither this effect nor any signs of discomfort in fish behavior were observed, which was probably due to the much lower dose of PAA: 15 L PAA d −1 , to inlet water of 32-33 L s −1 (5.2 • 10 −3 -5.4 • 10 −3 L PAA m −3 ), and 4-6 L PAA d −1 to the aeration system of the depuration tanks (1.4 • 10 −3 -2.1 • 10 −3 L PAA m −3 ). Fish can adapt to moderate (0.2-1 mg PAA L −1 for 6 weeks) PAA concentrations (Gesto et al 2018).…”